Andrés Castell-Rodríguez

On the mechanisms of action of short-term levonorgestrel administration in emergency contraception

The effects of short-term administration of levonorgestrel (LNG) at different stages of the ovarian cycle on the pituitary-ovarian axis, corpus luteum function, and endometrium were investigated. Forty-five surgically sterilized women were studied during two menstrual cycles. In the second cycle, each women received two doses of 0.75 mg LNG taken 12 h apart on day 10 of the cycle (Group A), at the time of serum luteinizing hormone (LH) surge (Group B), 48 h after positive detection of urinary LH (Group C), or late follicular phase (Group D). In both cycles, transvaginal ultrasound and serum LH were performed from the detection of urinary LH until ovulation. Serum estradiol (E2) and progesterone (P(4)) were measured during the complete luteal phase. In addition, an endometrial biopsy was taken at day LH + 9. Eighty percent of participants in Group A were anovulatory, the remaining (three participants) presented significant shortness of the luteal phase with notably lower luteal P4 serum concentrations. In Groups B and C, no significant differences on either cycle length or luteal P4 and E2 serum concentrations were observed between the untreated and treated cycles. Participants in Group D had normal cycle length but significantly lower luteal P4 serum concentrations. Endometrial histology was normal in all ovulatory-treated cycles. It is suggested that interference of LNG with the mechanisms initiating the LH preovulatory surge depends on the stage of follicle development. Thus, anovulation results from disrupting the normal development and/or the hormonal activity of the growing follicle only when LNG is given preovulatory. In addition, peri- and post-ovulatory administration of LNG did not impair corpus luteum function or endometrial morphology.

Hypoglycemic effect of Carica papaya leaves in streptozotocin-induced diabetic rats

BackgroundTraditional plant treatment for diabetes has shown a surging interest in the last few decades. Therefore, the purpose of this study was to assess the hypoglycemic effect of the aqueous extract of C. papaya leaves in diabetic rats. Several studies have reported that some parts of the C. papaya plant exert hypoglycemic effects in both animals and humans.MethodsDiabetes was induced in rats by intraperitoneal administration of 60 mg/kg of streptozotocin (STZ). The aqueous extract of C. papaya was administered in three different doses (0.75, 1.5 and 3 g/100 mL) as drinking water to both diabetic and non-diabetic animals during 4 weeks.ResultsThe aqueous extract of Carica papaya (0.75 g and 1.5 g/100 mL) significantly decreased blood glucose levels (p<0.05) in diabetic rats. It also decreased cholesterol, triacylglycerol and amino-transferases blood levels. Low plasma insulin levels did not change after treatment in diabetic rats, but they significantly increased in non-diabetic animals. Pancreatic islet cells were normal in non-diabetic treated animals, whereas in diabetic treated rats, C. papaya could help islet regeneration manifested as preservation of cell size. In the liver of diabetic treated rats, C. papaya prevented hepatocyte disruption, as well as accumulation of glycogen and lipids. Finally, an antioxidant effect of C. papaya extract was also detected in diabetic rats.ConclusionsThis study showed that the aqueous extract of C. papaya exerted a hypoglycemic and antioxidant effect; it also improved the lipid profile in diabetic rats. In addition, the leaf extract positively affected integrity and function of both liver and pancreas.

ATPase and MHC class II molecules co-expression in Rana pipiens dendritic cells

Mammalian Langerhans cells are antigen-presenting cells located in different epithelia. These cells have a characteristic ultrastructural pattern, present a plasmatic membrane ATPase activity and constitutively express class II molecules of the major histocompatibility complex. ATPase-positive dendritic cells that are morphologically similar to Langerhans cells have also been found in amphibian epidermis. In order to demonstrate that ATPase-positive dendritic cells of amphibian epidermis express class II molecules and are present in other stratified epithelia, histochemical and immunohistochemical as well as ultrastructural analysis were performed. ATPase-positive dendritic cells and class II-positive dendritic cells were observed in epidermis, nictitant membrane and cornea. In epidermis the number of ATPase-positive dendritic cells was 656+/-186/mm2 while class II-positive dendritic cells was 119+/-45/mm2. Some ATPase-positive dendritic cells showed co-expression of class II molecules. These results suggest the existence of dendritic cell subsets in amphibians as is clearly demonstrated in mammals.

Jak3 Is Involved in Dendritic Cell Maturation and CCR7- Dependent Migration

Background CCR7-mediated signalling is important for dendritic cell maturation and homing to the lymph nodes. We have previously demonstrated that Jak3 participates in the signalling pathway of CCR7 in T lymphocytes. Methodology and Principal Findings Here, we used Jak3−/− mice to analyze the role of Jak3 in CCR7-mediated dendritic cells migration and function. First, we found no differences in the generation of DCs from Jak3−/− bone marrow progenitors, when compared to wild type cells. However, phenotypic analysis of the bone marrow derived DCs obtained from Jak3−/− mice showed reduced expression of co-stimulatory molecules compared to wild type (Jak3+/+). In addition, when we analyzed the migration of Jak3−/− and Jak3+/+ mature DCs in response to CCL19 and CCL21 chemokines, we found that the absence of Jak3 results in impaired chemotactic responses both in vitro and in vivo. Moreover, lymphocyte proliferation and contact hypersensitivity experiments showed that DC-mediated T lymphocyte activation is reduced in the absence of Jak3. Conclusion/Significance Altogether, our data provide strong evidence that Jak3 is important for DC maturation, migration and function, through a CCR7-mediated signalling pathway.

Non-specific Esterase-positive Dendritic Cells in Epithelia of the Frog Rana Pipiens

Langerhans cells are antigen-presenting cells located in epithelia and have a dendritic outline, a convoluted nucleus surrounded by an electron lucent cytoplasm with sparse organelles and occasionally containing the characteristic Birbeck granule; their membrane contains class II molecules of the major histocompatibility complex and a strong membrane reactivity for both ATPase and non-specific esterase. Despite increasing knowledge about mammalian Langerhans cells, only a few studies have examined the possible occurrence of Langerhans-like cells in lower vertebrates. Our group has previously demonstrated the presence of dendritic cells in different epithelial membranes co-expressing a strong membrane ATPase reactivity and class II molecules of the major histocompatibility complex in the frog Rana pipiens. Adding another criterion in the characterization of Langerhans-like cells in amphibians, we now report evidence for the expression of membrane non-specific esterase reactivity in dendritic cells located in the epidermis, nictitant membrane and cornea with topographical and light and electron microscopical characteristics identical to those previously described for dendritic cells positive for ATPase and major histocompatibility complex class II in Rana pipiens. We postulate that, taking all this data together, these dendritic intraepithelial cells constitute the amphibian counterpart of mammalian Langerhans cells.

Role of Epidermal Dendritic Cells in Drug-Induced Cutaneous Adverse Reactions

Drug-induced adverse reactions (ADR) include any undesirable pharmacological effect that occurs following drug administration at therapeutic doses. The appearance of ADR significantly limits the use of drugs in as much as their clinical symptoms may range from very mild discomfort such as cutaneous rash, up to very severe, or even fatal tissue necrolysis such as the Stevens Johnson syndrome.One of the most frequently involved organ during ADR is the skin. Drug-induced cutaneous reactions (CDR) incidence is variable but they may appear in 2-3% of ambulatory patients, and it may increase to 10-15% when patients are hospitalized, or even be as high as 60% when co morbidity includes the presence of virus, bacteria, or parasites.Due to the fact that skin is one of the organs most frequently involved in ADR, in this work we analyze and propose a mechanism by which epidermal dendritic cells operating as the sentinels of the skin neuro-immune-endocrine system may contribute to CDR via either immunogenic or tolerogenic immune responses towards drugs, whenever they are administered topic or systemically.

GK-1 Improves the Immune Response Induced by Bone Marrow Dendritic Cells Loaded with MAGE-AX in Mice with Melanoma

The aim of dendritic cell (DC) vaccination in cancer is to induce tumor-specific effector T cells that may reduce and control tumor mass. Immunostimulants that could drive a desired immune response are necessary to be found in order to generate a long lasting tumor immune response. GK-1 peptide, derived from Taenia crassiceps, induces not only increase in TNFα, IFNγ, and MCP-1 production in cocultures of DCs and T lymphocytes but also immunological protection against influenza virus. Moreover, the aim of this investigation is the use of GK-1 as a bone marrow DCs (BMDCs) immunostimulant targeted with MAGE antigen; thus, BMDC may be used as immunotherapy against murine melanoma. GK-1 induced in BMDCs a meaningful increment of CD86 and IL-12. In addition, the use of BMDCs TNFα/GK-1/MAGE-AX induced the highest survival and the smallest tumors in mice. Besides, the treatment helped to increase CD8 lymphocytes levels and to produce IFNγ in lymph nodes. Moreover, the histopathological analysis showed that BMDCs treated with GK-1/TNFα and loaded with MAGE-AX induced the apparition of more apoptotic and necrotic areas in tumors than in mice without treatment. These results highlight the properties of GK-1 as an immunostimulant of DCs and suggest as a potential candidate the use of this immunotherapy against cancer disease.

Neurons and satellite glial cells in adult rat lumbar dorsal root ganglia express connexin 36

Previous studies have shown that following peripheral nerve injury there was a downregulation of the gap junction protein connexin 36 (Cx36) in the spinal cord; however, it is not known whether Cx36 protein is expressed in the dorsal root ganglia (DRGs), nor if its levels are altered following peripheral nerve injuries. Here we address these aspects in the adult rat lumbar DRG. Cx36 mRNA was detected using qRT-PCR, and Cx36 protein was identified in DRG sections using immunohistochemistry (IHC) and immunofluorescence (IF). Double staining revealed that Cx36 co-localizes with both anti-β-III tubulin, a neuronal marker, and anti-glutamine synthetase, a satellite glial cell (SGC) marker. In neurons, Cx36 staining was mostly uniform in somata and fibers of all sizes and its intensity increased at the cell membranes. This labeling pattern was in contrast with Cx36 IF dots mainly found at junctional membranes in islet beta cells used as a control tissue. Co-staining with anti-Cx43 and anti-Cx36 showed that whereas mostly uniform staining of Cx36 was found throughout neurons and SGCs, Cx43 IF puncta were localized to SGCs. Cx36 mRNA was expressed in normal lumbar DRG, and it was significantly down-regulated in L4 DRG of rats that underwent sciatic nerve injury resulting in persistent hypersensitivity. Collectively, these findings demonstrated that neurons and SGCs express Cx36 protein in normal DRG, and suggested that perturbation of Cx36 levels may contribute to chronic neuropathic pain resulting from a peripheral nerve injury.

Structural Effect of Different EDC Crosslinker Concentration in Gelatin- Hyaluronic Acid Scaffolds

Introduction: Gelatin and hyaluronic acid are two biopolymers with different applications in tissue engineering. They may be employed to construct diverse scaffolds that allow cells to differentiate and proliferate on them. In order to obtain the best functional and mechanical conditions in scaffolds, they must be crosslinked to form covalent links between gelatin and hyaluronic acid. The crosslinker 1-ethy-3-(3-dymethylaminopropyl) carbodiimide hydrochloride (EDC) is a compound widely used due to its low cytotoxicity. Besides, the concentration of the crosslinker may modify the physical properties and morphological characteristics of scaffolds when it forms covalent links between biopolymers, helping to construct different kinds of scaffolds used for developing soft tissues. However, the development of scaffolds made of gelatin and hyaluronic acid crosslinked with EDC has been poorly studied. In addition, the concentrations used for crosslinking gelatin and hyaluronic acid are contradictory. Therefore, the aim of this study was to analyze the structure of gelatin/hyaluronic acid scaffolds crosslinked with EDC. Methods: Gelatin-hyaluronic acid scaffolds were prepared by direct freeze-drying. Afterwards, They were crosslinked with different concentrations of EDC (6, 30, 50 and 60 mM) for 12 h. Results: This research has demonstrated that the gelatin/hyaluronic acid scaffolds crosslinked with the highest concentrations of the crosslinker had fewer water concentration absorbed, pore size diminished and pore number increased in comparison with control groups. Despite scaffolds composition has not changed in any of the concentrations, the bone marrow mesenchymal cells mortality percentage increased when cells were placed on the scaffolds of concentration 60 mM, perhaps for the residual 1-ethy-3-(3-dymethylaminopropyl) carbodiimide hydrochloride found in the scaffolds. Conclusion: Our results revealed that different EDC concentrations may modify the physical and biological characteristics of gelatin/hyaluronic acid scaffolds; as a result, the scaffolds obtained may be used for the manufacture of different tissues in regenerative medicine.

Corrigendum to “GK-1 Improves the Immune Response Induced by Bone Marrow Dendritic Cells Loaded with MAGE-AX in Mice with Melanoma”

In the paper titled “GK-1 Improves the Immune Response Induced by Bone Marrow Dendritic Cells Loaded with MAGE-AX in Mice with Melanoma” [1] the phrase “Recently, it has been reported that subcutaneous administration of GK-1 in mice with melanoma induces regression of the tumor mass and increases survival” should be as follows: “Recently, our group has shown that subcutaneous administration of GK-1 and DCs in mice with melanoma induces regression of the tumor mass and increases survival (unpublished data).”